1. Field of the Invention
The present invention relates generally to a transmission primarily intended for motor vehicle use, and more particularly to a torque converter for a transmission.
2. Description of the Related Art
Generally speaking, land vehicles require three basic components. These components include a power plant (such as an internal combustion engine), a power train and wheels. The power train's main component is typically referred to as the "transmission" Engine torque and speed are converted in the transmission in accordance with the tractive-power demand of the vehicle. A conventional automatic transmission includes a hydrodynamic torque converter to transfer engine torque from the engine crankshaft to a rotatable input member of the transmission through fluid-flow forces. Examples of such torque converters are disclosed in U.S. Pat. Nos. 4,240,532 and 4,289,048 which are assigned to the same assignee as the present invention.
One disadvantage of the above patented torque converters is that the transmission torque capacity is not fully utilized when mated with lower torque engines. Another disadvantage is that there is no torque compounding or multiplication for the engine input above the torque converter's coupling point speed. Yet another disadvantage is that there is no means for making a ratio shift (upshift/downshift) within these units.